1. Field of the Invention
The present invention relates to faucet sprayheads, and more particularly to a pull-down sprayhead docking mechanism for kitchen faucets that provides significantly less force to dock than to undock, and a longer operational lifetime.
2. Description of the Background
Faucets, especially kitchen faucets, are commercially available in numerous designs and configurations. Many are equipped with pull-out spray heads that enable more flexible cleaning. There are a variety of docking mechanisms which facilitate removal and return of the spray head from the faucet. These include twist-and-lock docking mechanisms, compression-fit or detent-lock docking mechanisms, and magnetic docking mechanisms. Design goals for such docking mechanisms include ease of docking, secure retention of the sprayhead when docked, ease of undocking, and consistent operation without degradation of the foregoing qualities over a long operational lifetime.
An example of a detent-lock mechanism is U.S. Pat. No. 6,845,526 to Malek et al. issued Jan. 25, 2005, which shows a pullout spray head with detent-fit docking collar with enhanced retaining force. The docking collar has an annular wall with a plurality of U-shaped slots which define a plurality of cantilevered snap fingers that fit into grooves in the connecting shaft when the spray head is docked.
Many mechanical docking designs on the market today rely on crush ribs to provide the necessary sprayhead retention. A form of detent-lock, these crush ribs about the base of the sprayhead or inside the faucet head deform during insertion to facilitate engagement there between. Unfortunately after several cycles the crush rib material abrades and retention decreases.
U.S. Pat. No. 6,619,567 to Ouyoung issued Sep. 16, 2003 shows a flexible water tap with pull-out sprayhead that uses a friction-fit dock (FIG. 8).
U.S. Pat. No. 7,699,241 to Benstead issued Apr. 20, 2010 shows a docking collar for a pull-out spray head. This docking collar includes a spring ring.
U.S. Pat. No. 7,909,061 to Nelson issued Mar. 22, 2011 shows a magnetic coupling for releasably coupling the faucet head to the faucet body.
Of the foregoing and others, only the magnetic couplings provide a differential docking force, vis-à-vis a uniform attractive force whether the sprayhead is being docked or undocked.
Magnets, however, are expensive. A purely mechanical docking system would be preferable, but in this context there are no known efforts to provide a differential docking force, requiring less force to dock than to undock. Moreover, conventional crush-rib type designs wear out and lose their retention ability. What is needed is a mechanical docking system that allows for the retention geometry to flex in order to reduce wear and tear, thereby prolonging the operational lifetime.
The present invention provides a purely mechanical docking system that requires significantly less force to dock than to undock, keeps the pull-down sprayhead securely in place when docked, and maintains registry of the internal components so that the spray head dock will never sag or degrade. Moreover, the retention geometry eliminates wear and tear of components resulting in a longer operational lifetime without any performance degradation.